Anarcha-feminism, also known as anarchist feminism or anarcho-feminism, is a system of analysis which combines the principles and power analysis of anarchist theory with feminism. It closely resembles intersectional feminism. Anarcha-feminism generally posits that patriarchy and traditional gender roles as manifestations of involuntary coercive hierarchy should be replaced by decentralized free association. Anarcha-feminists believe that the struggle against patriarchy is an essential part of class conflict and the anarchist struggle against the state and capitalism. In essence, the philosophy sees anarchist struggle as a necessary component of feminist struggle and vice versa. Canadian anarcha-feminist writer L. Susan Brown claims that "as anarchism is a political philosophy that opposes all relationships of power, it is inherently feminist".

Anarchism first emerged as a political current at a time when gender inequality was systematically enforced and women were excluded from public life. Their existence was confined to the traditional gender roles of mothers and wives, within the construct of the nuclear family. In particular, working-class women were both politically and economically disenfranchised, which drove them closer to socialism and political militancy. They began to agitate for reproductive rights and free love, which formed the basis for an anarchist feminism.

The earliest proponents of anarchism were initially reluctant to approach the subject of feminism: Pierre-Joseph Proudhon was openly hostile to feminist demands of gender equality and upheld traditional family values; Peter Kropotkin thought that feminist goals should be subordinated to the class struggle; and Benjamin Tucker opposed the demand of "equal pay for equal work". It was only after Mikhail Bakunin made the abolition of gender inequality one of the aims of the International Alliance of Socialist Democracy that women's rights became a primary concern for the anarchist movement. Anarcho-communists adopted Friedrich Engels' critique of the family, which held it to be the origin of both gender inequality and economic inequality. This anti-authoritarian critique of power within the institutions of marriage and the nuclear family began to attract many feminists towards anarchism. The subsequent synthesis of anarchism and feminism, although not explicitly labelled as such at the time, later came to be known as anarcha-feminism.

During the 1880s, a current of anarchist feminism was first developed by the Catalan activists Teresa Mañé and Teresa Claramunt. By the 1890s, anarchist feminism had spread across the globe, brought by immigrants to and from Europe. The anarchist press started to publish feminist analyses on gender equality and critiques of marriage, the nuclear family and prostitution. Through Errico Malatesta's La Questione Sociale, Teresa Mañé's pamphlets on female education and gender inequality received widespread publication. Anarchist feminism was further taken up by the American anarchists Voltairine de Cleyre and Emma Goldman, the latter of whom came to be considered a "founding mother" of anarcha-feminism. Lucy Parsons also established the Working Women's Union in Chicago and ensured women's participation in the Industrial Workers of the World as one of its founding members. In England, the anarchist Charlotte Wilson became an advocate for "equal pay for equal work" and promoted women's education.

Anarchist women took prominent positions within the editorial boards of magazines (such as Mother Earth), in the publication of books, and as public speakers. Specifically feminist publications were also circulated, including Germinal, El Oprimido and La Voz de la Mujer, in which anarchist women defended a revolutionary form of feminism. As a way to counter the Culture of Domesticity, which upheld the private property of the nuclear family, anarchist women like Charlotte Wilson opened their homes into "quasi-public spaces" for political meetings and communal meals. Anarchist women even took part in violent direct actions, including Vera Zasulich's attempted assassination of the Russian police chief Fyodor Trepov; Germaine Berton's murder of the French far-right politician Marius Plateau; and Kanno Sugako's plot to assassinate the Japanese Emperor Meiji.

The rise of anarchist feminism provoked an anti-feminist reaction among many of the men of the anarchist movement, who deemphasised the struggle for women's rights as secondary to the class struggle. In turn, La Voz de la Mujer denounced these men as "false anarchists" who prioritised their own liberation over that of women. In the Chinese anarcha-feminist journal Natural Justice, He Zhen also criticised what she saw as "men's pursuit of self distinction in the name of women's liberation". Anarcha-feminists generally concluded that male hostility to feminism proved them unreliable to the cause for women's rights, and began to organise their own movement to address their own needs.

First-wave feminists established women's groups as flat organizations that used consensus decision-making, reflecting an "unconscious libertarian consciousness". Anarchist women's groups were established throughout the United States, largely by Italian immigrant women, with the goal of pursuing "women's emancipation" through mutual aid and self-organization. In Paterson, New Jersey, the Gruppo Emancipazione della Donna formed women's theater and music clubs, and publicised works of anarchist feminism that linked the struggle against the patriarchy with the struggle against the patria. In contrast to the Italian anarchists, Jewish anarchists rarely formed specific women's groups, with anarchists of the journal Fraye Arbeter Shtime declaring themselves to all be feminists.

One of the most notable libertarian women's groups was the Mujeres Libres, an anarchist feminist organisation that aimed for women's liberation from their "triple enslavement" by ignorance, exploitation and discrimination. Founded during the Spanish Revolution of 1936 by Lucía Sánchez Saornil, Mercè Comaposada and Amparo Poch y Gascón, the Mujeres Libres implemented programmes of women's education that taught women technical skills and increased female literacy. Sánchez Saornil herself wrote poetry that called for women to take action against their oppression, which attracted Emma Goldman to visit Spain and participate in the work of the Mujeres Libres as an advocate.